Ilia Denisov
b47c47e969
Extract the FlatBuffers builders for the wire tables shared by the backend push encoder and the gateway edge transcoder — GameView, MoveRecord, StateView, AccountRef, Invitation and their nested rows — into a new scrabble/pkg/wire package. Both callers keep their local builder signatures (no call sites move) but now map their own source types (the backend's notify.* payloads and the decoded engine.MoveRecord; the gateway's backendclient.* REST DTOs) to neutral wire.* structs and delegate the construction to package wire, the single definition of the nested-table layout. Behaviour-preserving: the verified-identical field sets mean the wire bytes decode the same, and the notify + transcode round-trip tests pass unchanged. The fiddly Start/Add/End + reverse-prepend vector boilerplate now lives once; the two encode files shrink while pkg/wire carries the shared logic.
374 lines
12 KiB
Go
374 lines
12 KiB
Go
package transcode
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import (
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flatbuffers "github.com/google/flatbuffers/go"
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"scrabble/gateway/internal/backendclient"
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fb "scrabble/pkg/fbs/scrabblefb"
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"scrabble/pkg/wire"
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)
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// The encoders build the FlatBuffers response payloads from the backend's typed
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// responses. FlatBuffers is built bottom-up: every string and child vector is
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// created before the table that references it, and no two tables/vectors are
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// under construction at once.
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// buildSupportedLanguagesVector creates the Session.supported_languages [string]
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// vector from langs. FlatBuffers is built bottom-up, so the caller must invoke this
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// (which itself creates the element strings) before SessionStart and with no table
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// under construction.
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func buildSupportedLanguagesVector(b *flatbuffers.Builder, langs []string) flatbuffers.UOffsetT {
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offsets := make([]flatbuffers.UOffsetT, len(langs))
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for i, lang := range langs {
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offsets[i] = b.CreateString(lang)
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}
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fb.SessionStartSupportedLanguagesVector(b, len(langs))
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for i := len(offsets) - 1; i >= 0; i-- {
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b.PrependUOffsetT(offsets[i])
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}
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return b.EndVector(len(langs))
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}
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// encodeSession builds a Session payload. supportedLangs is the service's set of
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// offered game languages, which the UI gates the New Game variant choice by.
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func encodeSession(s backendclient.SessionResp, supportedLangs []string) []byte {
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b := flatbuffers.NewBuilder(128)
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token := b.CreateString(s.Token)
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uid := b.CreateString(s.UserID)
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name := b.CreateString(s.DisplayName)
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langs := buildSupportedLanguagesVector(b, supportedLangs)
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fb.SessionStart(b)
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fb.SessionAddToken(b, token)
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fb.SessionAddUserId(b, uid)
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fb.SessionAddIsGuest(b, s.IsGuest)
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fb.SessionAddDisplayName(b, name)
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fb.SessionAddSupportedLanguages(b, langs)
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b.Finish(fb.SessionEnd(b))
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return b.FinishedBytes()
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}
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// encodeAck builds an Ack payload.
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func encodeAck(ok bool) []byte {
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b := flatbuffers.NewBuilder(16)
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fb.AckStart(b)
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fb.AckAddOk(b, ok)
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b.Finish(fb.AckEnd(b))
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return b.FinishedBytes()
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}
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// encodeProfile builds a Profile payload.
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func encodeProfile(p backendclient.ProfileResp) []byte {
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b := flatbuffers.NewBuilder(192)
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uid := b.CreateString(p.UserID)
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name := b.CreateString(p.DisplayName)
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lang := b.CreateString(p.PreferredLanguage)
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tz := b.CreateString(p.TimeZone)
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awayStart := b.CreateString(p.AwayStart)
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awayEnd := b.CreateString(p.AwayEnd)
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fb.ProfileStart(b)
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fb.ProfileAddUserId(b, uid)
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fb.ProfileAddDisplayName(b, name)
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fb.ProfileAddPreferredLanguage(b, lang)
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fb.ProfileAddTimeZone(b, tz)
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fb.ProfileAddHintBalance(b, int32(p.HintBalance))
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fb.ProfileAddBlockChat(b, p.BlockChat)
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fb.ProfileAddBlockFriendRequests(b, p.BlockFriendRequests)
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fb.ProfileAddIsGuest(b, p.IsGuest)
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fb.ProfileAddAwayStart(b, awayStart)
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fb.ProfileAddAwayEnd(b, awayEnd)
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fb.ProfileAddNotificationsInAppOnly(b, p.NotificationsInAppOnly)
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b.Finish(fb.ProfileEnd(b))
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return b.FinishedBytes()
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}
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// encodeLinkResult builds a LinkResult payload. A switched-session token
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// (a guest initiator whose durable counterpart won) is carried as a nested Session
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// for the client to adopt; it is omitted otherwise. supportedLangs is the variant
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// gating set for that switched session — the link flows run on the web, so it is the
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// gateway's default (non-platform) set.
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func encodeLinkResult(r backendclient.LinkResultResp, supportedLangs []string) []byte {
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b := flatbuffers.NewBuilder(256)
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status := b.CreateString(r.Status)
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secID := b.CreateString(r.SecondaryUserID)
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secName := b.CreateString(r.SecondaryName)
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hasSession := r.Token != "" && r.Profile != nil
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var sess flatbuffers.UOffsetT
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if hasSession {
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token := b.CreateString(r.Token)
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uid := b.CreateString(r.Profile.UserID)
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name := b.CreateString(r.Profile.DisplayName)
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langs := buildSupportedLanguagesVector(b, supportedLangs)
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fb.SessionStart(b)
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fb.SessionAddToken(b, token)
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fb.SessionAddUserId(b, uid)
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fb.SessionAddIsGuest(b, r.Profile.IsGuest)
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fb.SessionAddDisplayName(b, name)
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fb.SessionAddSupportedLanguages(b, langs)
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sess = fb.SessionEnd(b)
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}
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fb.LinkResultStart(b)
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fb.LinkResultAddStatus(b, status)
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fb.LinkResultAddSecondaryUserId(b, secID)
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fb.LinkResultAddSecondaryDisplayName(b, secName)
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fb.LinkResultAddSecondaryGames(b, int32(r.SecondaryGames))
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fb.LinkResultAddSecondaryFriends(b, int32(r.SecondaryFriends))
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if hasSession {
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fb.LinkResultAddSession(b, sess)
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}
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b.Finish(fb.LinkResultEnd(b))
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return b.FinishedBytes()
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}
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// encodeMoveResult builds a MoveResult payload.
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func encodeMoveResult(r backendclient.MoveResultResp) []byte {
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b := flatbuffers.NewBuilder(512)
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move := buildMoveRecord(b, r.Move)
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game := buildGameView(b, r.Game)
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rackBytes := make([]byte, len(r.Rack))
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for i, v := range r.Rack {
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rackBytes[i] = byte(v)
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}
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rack := b.CreateByteVector(rackBytes)
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fb.MoveResultStart(b)
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fb.MoveResultAddMove(b, move)
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fb.MoveResultAddGame(b, game)
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fb.MoveResultAddRack(b, rack)
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fb.MoveResultAddBagLen(b, int32(r.BagLen))
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b.Finish(fb.MoveResultEnd(b))
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return b.FinishedBytes()
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}
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// encodeState builds a StateView payload. The rack is a vector of alphabet indices and the
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// alphabet display table is included only when the backend returned it (the
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// client requests it on a per-variant cache miss).
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func encodeState(s backendclient.StateResp) []byte {
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b := flatbuffers.NewBuilder(512)
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b.Finish(wire.BuildStateView(b, toWireState(s)))
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return b.FinishedBytes()
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}
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// toWireState maps a StateResp to the shared wire.StateView.
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func toWireState(s backendclient.StateResp) wire.StateView {
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alphabet := make([]wire.AlphabetEntry, len(s.Alphabet))
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for i, e := range s.Alphabet {
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alphabet[i] = wire.AlphabetEntry{Index: e.Index, Letter: e.Letter, Value: e.Value}
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}
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return wire.StateView{
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Game: toWireGame(s.Game),
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Seat: s.Seat,
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Rack: s.Rack,
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BagLen: s.BagLen,
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HintsRemaining: s.HintsRemaining,
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Alphabet: alphabet,
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}
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}
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// encodeMatch builds a MatchResult payload.
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func encodeMatch(m backendclient.MatchResp) []byte {
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b := flatbuffers.NewBuilder(512)
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matched := m.Matched && m.Game != nil
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var game flatbuffers.UOffsetT
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if matched {
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game = buildGameView(b, *m.Game)
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}
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fb.MatchResultStart(b)
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fb.MatchResultAddMatched(b, matched)
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if matched {
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fb.MatchResultAddGame(b, game)
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}
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b.Finish(fb.MatchResultEnd(b))
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return b.FinishedBytes()
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}
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// buildChatMessage builds a ChatMessage table and returns its offset.
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func buildChatMessage(b *flatbuffers.Builder, c backendclient.ChatResp) flatbuffers.UOffsetT {
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id := b.CreateString(c.ID)
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gid := b.CreateString(c.GameID)
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sid := b.CreateString(c.SenderID)
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kind := b.CreateString(c.Kind)
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body := b.CreateString(c.Body)
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fb.ChatMessageStart(b)
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fb.ChatMessageAddId(b, id)
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fb.ChatMessageAddGameId(b, gid)
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fb.ChatMessageAddSenderId(b, sid)
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fb.ChatMessageAddKind(b, kind)
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fb.ChatMessageAddBody(b, body)
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fb.ChatMessageAddCreatedAtUnix(b, c.CreatedAtUnix)
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return fb.ChatMessageEnd(b)
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}
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// encodeChat builds a ChatMessage payload.
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func encodeChat(c backendclient.ChatResp) []byte {
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b := flatbuffers.NewBuilder(192)
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b.Finish(buildChatMessage(b, c))
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return b.FinishedBytes()
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}
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// encodeHintResult builds a HintResult payload.
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func encodeHintResult(r backendclient.HintResultResp) []byte {
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b := flatbuffers.NewBuilder(512)
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move := buildMoveRecord(b, r.Move)
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fb.HintResultStart(b)
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fb.HintResultAddMove(b, move)
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fb.HintResultAddHintsRemaining(b, int32(r.HintsRemaining))
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b.Finish(fb.HintResultEnd(b))
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return b.FinishedBytes()
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}
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// encodeEvalResult builds an EvalResult payload.
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func encodeEvalResult(r backendclient.EvalResultResp) []byte {
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b := flatbuffers.NewBuilder(256)
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words := buildStringVector(b, r.Words, fb.EvalResultStartWordsVector)
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fb.EvalResultStart(b)
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fb.EvalResultAddLegal(b, r.Legal)
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fb.EvalResultAddScore(b, int32(r.Score))
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fb.EvalResultAddWords(b, words)
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b.Finish(fb.EvalResultEnd(b))
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return b.FinishedBytes()
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}
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// encodeWordCheck builds a WordCheckResult payload.
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func encodeWordCheck(r backendclient.WordCheckResp) []byte {
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b := flatbuffers.NewBuilder(64)
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word := b.CreateString(r.Word)
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fb.WordCheckResultStart(b)
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fb.WordCheckResultAddWord(b, word)
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fb.WordCheckResultAddLegal(b, r.Legal)
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b.Finish(fb.WordCheckResultEnd(b))
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return b.FinishedBytes()
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}
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// encodeDraftView builds a DraftView payload wrapping the player's composition JSON. The
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// string is empty for the save acknowledgement (the client ignores that payload).
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func encodeDraftView(jsonStr string) []byte {
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b := flatbuffers.NewBuilder(256)
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j := b.CreateString(jsonStr)
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fb.DraftViewStart(b)
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fb.DraftViewAddJson(b, j)
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b.Finish(fb.DraftViewEnd(b))
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return b.FinishedBytes()
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}
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// encodeHistory builds a History payload (the decoded move journal).
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func encodeHistory(r backendclient.HistoryResp) []byte {
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b := flatbuffers.NewBuilder(1024)
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moveOffs := make([]flatbuffers.UOffsetT, len(r.Moves))
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for i, m := range r.Moves {
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moveOffs[i] = buildMoveRecord(b, m)
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}
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fb.HistoryStartMovesVector(b, len(moveOffs))
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for i := len(moveOffs) - 1; i >= 0; i-- {
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b.PrependUOffsetT(moveOffs[i])
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}
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moves := b.EndVector(len(moveOffs))
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gid := b.CreateString(r.GameID)
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fb.HistoryStart(b)
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fb.HistoryAddGameId(b, gid)
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fb.HistoryAddMoves(b, moves)
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b.Finish(fb.HistoryEnd(b))
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return b.FinishedBytes()
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}
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// encodeGameList builds a GameList payload (the caller's games).
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func encodeGameList(r backendclient.GameListResp) []byte {
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b := flatbuffers.NewBuilder(1024)
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gameOffs := make([]flatbuffers.UOffsetT, len(r.Games))
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for i, g := range r.Games {
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gameOffs[i] = buildGameView(b, g)
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}
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fb.GameListStartGamesVector(b, len(gameOffs))
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for i := len(gameOffs) - 1; i >= 0; i-- {
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b.PrependUOffsetT(gameOffs[i])
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}
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games := b.EndVector(len(gameOffs))
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fb.GameListStart(b)
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fb.GameListAddGames(b, games)
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b.Finish(fb.GameListEnd(b))
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return b.FinishedBytes()
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}
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// encodeChatList builds a ChatList payload (a game's chat history).
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func encodeChatList(r backendclient.ChatListResp) []byte {
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b := flatbuffers.NewBuilder(512)
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msgOffs := make([]flatbuffers.UOffsetT, len(r.Messages))
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for i, m := range r.Messages {
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msgOffs[i] = buildChatMessage(b, m)
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}
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fb.ChatListStartMessagesVector(b, len(msgOffs))
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for i := len(msgOffs) - 1; i >= 0; i-- {
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b.PrependUOffsetT(msgOffs[i])
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}
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msgs := b.EndVector(len(msgOffs))
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fb.ChatListStart(b)
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fb.ChatListAddMessages(b, msgs)
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b.Finish(fb.ChatListEnd(b))
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return b.FinishedBytes()
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}
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// buildGameView builds a GameView table and returns its offset.
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func buildGameView(b *flatbuffers.Builder, g backendclient.GameResp) flatbuffers.UOffsetT {
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return wire.BuildGameView(b, toWireGame(g))
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}
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// toWireGame maps a GameResp to the shared wire.GameView.
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func toWireGame(g backendclient.GameResp) wire.GameView {
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seats := make([]wire.SeatView, len(g.Seats))
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for i, s := range g.Seats {
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seats[i] = wire.SeatView{
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Seat: s.Seat,
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AccountID: s.AccountID,
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Score: s.Score,
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HintsUsed: s.HintsUsed,
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IsWinner: s.IsWinner,
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DisplayName: s.DisplayName,
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}
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}
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return wire.GameView{
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ID: g.ID,
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Variant: g.Variant,
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DictVersion: g.DictVersion,
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Status: g.Status,
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Players: g.Players,
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ToMove: g.ToMove,
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TurnTimeoutSecs: g.TurnTimeoutSecs,
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MoveCount: g.MoveCount,
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EndReason: g.EndReason,
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Seats: seats,
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LastActivityUnix: g.LastActivityUnix,
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}
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}
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// buildMoveRecord builds a MoveRecord table and returns its offset.
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func buildMoveRecord(b *flatbuffers.Builder, m backendclient.MoveRecordResp) flatbuffers.UOffsetT {
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tiles := make([]wire.TileRecord, len(m.Tiles))
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for i, t := range m.Tiles {
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tiles[i] = wire.TileRecord{Row: t.Row, Col: t.Col, Letter: t.Letter, Blank: t.Blank}
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}
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return wire.BuildMoveRecord(b, wire.MoveRecord{
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Player: m.Player,
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Action: m.Action,
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Dir: m.Dir,
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MainRow: m.MainRow,
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MainCol: m.MainCol,
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Tiles: tiles,
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Words: m.Words,
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Count: m.Count,
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Score: m.Score,
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Total: m.Total,
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})
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}
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// buildStringVector builds a vector of strings using the table-specific
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// StartXVector function and returns the vector offset.
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func buildStringVector(b *flatbuffers.Builder, items []string, start func(*flatbuffers.Builder, int) flatbuffers.UOffsetT) flatbuffers.UOffsetT {
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offs := make([]flatbuffers.UOffsetT, len(items))
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for i, s := range items {
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offs[i] = b.CreateString(s)
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}
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start(b, len(offs))
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for i := len(offs) - 1; i >= 0; i-- {
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b.PrependUOffsetT(offs[i])
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}
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return b.EndVector(len(offs))
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}
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